OBJECTIVE MARKERS OF CONDOM FAILURE

Background: Studies of condom efficacy rely on self-reported behavior. Objective markers of exposure to semen may provide a more valid asses sment of condom failure and failure to use condoms. Goals of this Stud y: To compare three semen biomarkers: acid phosphatase (AP) activity, prostate specific antigen (PSA), and the human seminal plasma antigen (MHS-5). Study Design: Twenty women were intravaginally inoculated wit h six measured, increasingly larger amounts of their partners' semen. Vaginal fluid was collected by the participant using swabs and tested. Results: Background levels of PSA were low (0.00-1.25 ng/ml), backgro und levels of AP were variable (0-350 U/l), and all preinoculation sam ples were negative for MHS-5. All postinoculation samples were positiv e for PSA, 64 of 117 (55%) for AP, and 14 of 120 (12%) for MHS-5. Conc lusion: The PSA immunoassay was the best semen biomarker under these s ampling and testing conditions.